Electric Motor Control Basics - Book - Page 66
Applying Motor Control in a Wastewater Application
Motor Protection Circuit Breakers
Most pump systems in the market today include basic motor protection built into the
motor or control box. This protection however is designed to safeguard against only
current problems, therefore additional motor protection should be considered. There
are many options available to choose from, each present slightly different performance
characteristics under overload conditions. Factors to consider are:
• High fault short circuit current rating because it assures safety and reliability in
extremely high fault applications.
• Trip indication helps determine the type of maintenance or service that may be
required by identifying the cause of tripping – short circuit or overload.
• Self-protection of these devices assures excellent motor protection and helps
eliminate the need for additional circuit breakers and upstream fuses.
Applications of Motor Controls in the Water and Wastewater Industry
Overload relays, contactors, and motor protection circuit breakers are largely used in
the following applications.
• Influent and Effluent Pumps: The influent pumps are usually placed at the start of
the wastewater treatment plant. The wastewater first enters into the influent
pump, which pumps it to other parts of the treatment plant. Effluent pumps are
used for treating water that may contain solids up to 3/4”.
• Booster Pumps: These pumps are used for boosting the water pressure for use in
light industrial and commercial applications. The booster pumps are mainly used for
potable water applications.
Part 1, Contactors
Basics: Part 2,
Basics: Part 3,
The Benefits of Type E/F
Basic Pump Control:
Three Phase DOL Starter
Control of an Electric Pump
Applying Motor Control
in a Wastewater
NEMA vs IEC Motor